Method of assembling a seal unit

ABSTRACT

A method for assembling a seal unit including two opposed conduit parts and a composite sealing ring adapted to be interposed therebetween. The sealing ring includes deformable material on the outer periphery and flexible sealing flanges extending about at least a portion of the deformable material. The seal is partially inserted into the cavity of one conduit part until the deformable material contacts the internal sealing surface of that part. Afterwards the second conduit part is placed over the exposed portion of the seal to cause the internal sealing surface of the second part to contact the deformable material. The two conduit parts are drawn together to thereby cause the deformable material to deformingly contact the internal surfaces of the conduit parts and are subsequently drawn further together to cause the deformable material to flex the sealing flanges of the sealing ring into engagement with the internal sealing surfaces of the conduit parts.

United States Patent Mason et al. 51 Aug. 1, 1972 METHOD OF ASSEMBLING A SEAL 3,398,978 8/1968 Gasche "285/367 X UNIT 3,403,931 10/1968 Crain et al. ..285/367 X [72] Inventors: John F. Mason; Bruce J. Frazier;

Norman L. Freemen, all of Duncan, Prlma'y Exammer charh? Moon Okla Attorney-John H. Tregomng, Thomas R. Weaver and Michael J. Caddell [73] Assignee: Halliburton Company, Duncan,

O [57] ABSTRACT Filed: June 1970 A method for assembling a seal unit including two op- 21 A l. N 45,3 8 posed conduit parts and a composite sealing ring 1 pp 0 9 adapted to be interposed therebetween. The sealing Related US. Application Data ring includes deformable material on the outer periphery and flexible sealing flanges extending about [62] E l 1 gg f f May 1968 at least a portion of the deformable material. The seal a is partially inserted into the cavity of one conduit part until the deformable material contacts the internal [52] US. Cl ..29/157, 29/428 Sealing Surface of that part Afterwards the Second [51] Int. (31.....B21d 53/00, B2lk 29/00, 823p 15/26 I 58] Field of Search 29 57 277/225 235 conduit part is placed over the exposed portlon of the 585/334 seal to cause the internal sealing surface of the second part to contact the deformable material. The two conduit parts are drawn together to thereby cause the [56] References cued deformable material to deformingly contact the inter- UNITED STATES PATENTS nal surfaces of the conduit parts and are subsequently drawn further together to cause the deformable 2,403,364 7/1946 Hertzell 61: al. ..277/225 material to flex the Sealing flanges of the Sealing ring 2,517,290 8/1950 De Moude et "277/225 into engagement with the internal sealing surfaces of 2,766,998 10/1956 Watts et a1 ..285/334.2 the conduit parts. 2,766,999 10/1956 Watts et al ..285/334.2 3,214,201 lO/l965 Fonda ..29/157 X 4 Claims, 4 Drawing Figures PATENTEDMJB 1 an I 3.680.188

. M u .wllllm TORS mvm JOHN F. MASON H6 3 BRUCE J. FRAZIER BY NORMAN L. FREEMAN,JR. A ra ms METHOD OF ASSEMBLING A SEAL UNIT RELATED APPLICATIONS BACKGROUND OF THE INVENTION This invention relates to a method for assembling a seal unit including two opposed conduit parts and a composite sealing ring to be interposed therebetween. In particular, this invention relates to such a method wherein the composite sealing ring is of the type having a relatively hard internal annular portion on which is mounted a flowable elastomeric material, the seal being adapted to be removably interposed between adjacent conduit parts.

In conducting fluid flow along a conduit, it has been common for many years to releasably join conduit sections in order to provide a conduit path of desired I length. It is often desirable to put some form of sealing unit between adjacent conduit sections so that leakage of fluid at the conduit joints may be avoided. To obtain a positive leak proof seal, it is desirable to force the seal member intopositive engagement with internal sealing surfaces of the conduit parts to be joined.

However, the force applied to the seal, while of a magnitude sufiicient to obtain positive sealing engagement, must not be so great as to detrimentally affect the sea]. In order to reduce the possibility of damaging the seal with excess pressure that forces the seal into engagement with the conduit, it has become necessary to employ seal rings of a substantially hard material such as steel.

At least one prior seal of this type includes a seal ring from which oppositely disposed flexible sealing lips extend in a generally axial direction. The seal ring is interposed-between'two adjacent conduit parts which are drawn together by a clamping arrangement. As the Although prior seals of the type described are often adequate, they may sometimes prove unsatisfactory for a number of reasons. For example, since the flexible sealing lips are made of a generally incompressible material such as steel, some small voids sometimes exist between the sealing lips and the internal sealing surfaces of the conduit parts. Therefore, with this type of assembly a truly leak proof seal may not always be obtained. Such a leak proof seal is highly desirably for any seal intended to be used with extreme high pressure fluid flow because of the destructive cutting action of small streams of fluid at high pressures.

Another disadvantage of the previously described prior structure resides in the fact that the flexible sealing lips are deflected radially inwardly with respect to the conduit parts. If the inward radial deflection is too great or too small, then a diameter change of the fluid flow path occurs at the point of the seal. Such a diameter change increases the possibility of creating turbulence at the conduit joint. In high volume fluid flow where the fluid contains abrasive particles such as is the case with fracturing work, it is desirable to minimize turbulence effects.

Furthermore, if the flexible lips of the previously described ring are overstressed or fatigued, the seal may be lost.

SUMMARY OF THE INVENTION It is, therefore, a general object of the invention to provide a seal assembly of the type used at fluid conduit joints intended to obviate or minimize disadvantages of the sort previously noted.

It is a particular object of the invention to provide a seal assembly at fluid conduit joints wherein substantially zero clearance is obtained between the seal member and the internal sealing surfaces of the conduit parts to be joined.

It is another object of the invention to provide a substantially fail-safe seal assembly having two independent sealing structures.

It is a further object of the invention to provide a seal assembly for conduit parts to be joined so designed that turbulence at the conduit joint is minimized.

It is a still further object of the invention to provide a method for assembling a seal unit wherein the method reduces the likelihood of any voids occurring between the seal and mating conduit sealing surfaces.

A preferred embodiment of the invention intended to accomplish at least some of the foregoing objects comprises a methodof assembling a seal unit wherein the seal unit includes two opposed conduit parts and a composite sealing ring adapted to be interposed between and to mate with the internal sealing surfaces of the conduit parts. The sealing ring includes an annular central rim portion from which two oppositely disposed lip portions extend axially outwardly. An elastomeric sealing member is mounted peripherally about each of the lip portions. The elastomeric material is adapted to be forced to conformingly contact internal sealing surfaces of the conduit parts when the sealing ring is interposed therebetween. Two oppositely disposed flexible sealing flanges also extend axially outwardly from the lip portions. Part of the elastomeric sealing material engages the flexible lip portions, so that any pressure tending to cause that part of the elastomeric material to redistribute its volume, will force the flexible sealing flanges radially outwardly into engagement with mating internal sealing surfaces of the conduit parts.

In order to align the conduit parts with respect to the sealing ring, rib means, extending generally radially outwardly from the central rim portion, is employed. The rib means acts as an alignment member by contacting opposing end faces of the conduit parts and thereby insuring a minimum of diametrical or directional change at the conduit joint.

A selectively operable connecting means is in contact with the conduit parts to be joined and is operative to draw them together by an initial amount. This initial amount is sufficient to cause the elastomeric material to conformingly contact the internal sealing surfaces of the conduits and form a first seal therewith. The connecting means is also operable to draw the conduit parts further together, so that the portions of the elastomeric material in contact with the flexible sealing flanges will redistribute their volume. The volume redistribution results in a force on the sealing flanges which causes them to engage the conduit sealing surfaces and form another seal therewith. The method of drawing the conduit parts together thereby provides a substantially fail-safe seal assembly including two independent seals.

Another aspect of the invention is that the internal diameter of the seal ring and the diameters of the flow passages in the conduit parts that are joined are substantially the same, thereby reducing the possibility of creating turbulence at the conduit joint.

THE DRAWINGS A seal assembly constructed in accordance with a preferred embodiment of the invention is illustrated in the accompanying drawings in which:

FIG. 1 is a partial cross sectional side view of a seal assembly according to a preferred embodiment of the present invention;

FIG. 2 is an end view of the seal assembly shown in FIG. 1 taken along the line 2-2 therein;

FIG. 3 is a cross sectional side view of one of the conduit parts shown in FIG. 1; and

FIG. 4 is a cross sectional view on an enlarged scale of the composite sealing member shown in FIG. 1 with the seal shown before insertion into the conduit parts.

DETAILED DESCRIPTION General Summary Referring to FIG. 1 of the drawings, a seal assembly according to a preferred embodiment of the invention is there shown. Y

The assembly includes a first conduit part 2 (FIG. 3) having an axially extending flow passage 4 which is radially intersected by an end face 6. Adjacent the end face, the conduit is provided with a sealing cavity 9 that is radially offset with respect to the flow passage 4.

A composite annular seal 8 (FIG. 4) is interposed between the conduit part 2 and a substantially identical but mirror image disposed, second conduit part 10. The seal'8 includes an inner annular ring 12 from which a generally axially extending first lip portion 14 projects into a sealing cavity 9 of the conduit part 2. A first elastomeric seal member 16 extends peripherally about the lip portion 14 and conformingly engages-the conduit part 2 in the sealing cavity 9. A second generally axially extending lip portion 18 and a second elastomeric sealing member 20 similarly extend into the second conduit part 10.

The seal ring 12 also includes a generally axially ex- I tending first flexible sealing flange 22 which projects into the sealing cavity 9 of the conduit part 2. A portion 24 of the elastomeric member 16 engages the flange 22. Similarly, extending into the conduit part is a second flexible sealing flange 26 which is engaged by a portion 28 of the elastomeric member 20.

Positioned-about conduit parts 2 and 10 is a clamping assembly 30 that is operative to draw the conduit parts together. The elastomeric members 16 and are thereby caused to redistribute their volumes and take up any small voids between the elastomer and the internal sealing surfaces of the conduits. The clamping assembly 30 is operative to draw the conduit parts further together and cause the portions 24 and 28 of the elastomeric members to force flexible sealing flanges 22 and 26 radially outwardly into engagement with the internal conduit sealing surfaces.

In this way, the elastomeric material forms a first seal and greatly increases the leak proof nature of the seal by conformingly contacting the internal sealing surfaces of the conduit.

Furthermore, a second seal is provided by the flexible sealing flanges 22 and 26. The possibility of ruining the sealing properties of the sealing flanges by fatigue or overstressing is reduced since the flanges are radially deflected in response to axial pressure on the conduit parts after the elastomer has initially redistributed its volume to take up small voids. If any axial pressure is applied to the elastomer, beyond that pressure which is needed to flex the flanges into sealing engagement, the elastomer may escape around lip portions 18 and 14 instead of exerting further pressure on the flanges.

Detailed Structure The previously mentioned composite annular seal 8 comprises an annular sealing ring 12 of relatively hard material such asmachined metal or the like. The ring 12 includes a central rim portion 34 and a plurality of radial and axial projections. The generally axially disposed lip portions 14 and 18 constitute the radially innermost projections extending from the rim portion 34. The lip portions 14 and 18 define annular, peripheral support shelves 36 and 38 respectively. Extending about these support shelves, is elastomeric sealing means comprising the two elastomeric members 16 and 20. Each of the elastomeric members has an undercut groove 17 and l9 facing radially inwardly of the seal. In the preferred embodiment shown in FIG. 4, the elastomeric members 16 and 20 are rings molded from I-Iycar and bonded to the support shelves 36 and 38. However, the particular material for the elastomeric sealing means is not critical, and it is only necessary that the material be such that it will flow slightly when compressive forces are exerted on it.

The previously described, generally axially disposed flexible sealing flanges 22 and 26 also extend oppositely outwardly from the central rim portion 34, but at a position radially outwardly from the lip portions 14 and 18. These flexible sealing flanges, together with their adjacent lip portions, define expandable support pockets 40 and 42 inwhich the seated portions 24 and 28 of the elastomeric material are inserted. Each of the flexible sealing flanges also includes an external sealing surface 44 and 46 adapted to mate with the internal sealing surfaces of the conduit parts 2 and 10.

The internal sealing surfaces of the conduit part 2 are formed in the previously mentioned internal sealing cavity 9 (FIG. 3) by a radially extending, annular internal sealing shoulder 48 which intersects an axially extending, annular internal sealing shoulder 50. For a purpose hereinafter described, the total internal axial length d, of the conduit part 2, from the sealing shoulder 48 to the end face 6, is greater than the axial extent d of the lip portion, but is less than the axial length d; of the seal member 8 when the elastomeric means is uncompressed (FIG. 4). The internal sealing cavity of the conduit part 10 is similarly defined.

The previously mentioned clamping assembly 30 includes two clamp pieces 31 and 33 mounted about the conduit parts 2 and in engagement with a first and second projection 52 and 54 formed on the radially outerrnost portions of the conduit parts 2 and 10 respectively. The assembly may be tightened to draw the conduit parts together by the conventional tangential draw bolts 56, 58 and 60. The particular clamping means used to draw the conduit parts together is not critical. The clamping arrangement shown could be replaced by inserting bolts through the projections 52 and 54 for quick disconnect service, or by any other structure that will enable an operator to pull the two conduits together and hold them.

When the composite seal 8 is interposed between the adjacent conduit parts 2 and 10 (FIG. 1), initial drawing pressure provided by the clamp assembly 30 will cause the elastomeric members 16 and 20 to flow slightly and fill small voids between the elastomeric members and the internal sealing shoulders 48 and 50 (FIG. 3) of the conduit. This flowing is caused by compression of the elastomeric members by the conduit parts 2 and 10 because the previously mentioned conduit axial dimension d is less than the axial lengths d defined by the axial extent of lip portions 14 and 18 and the axiallyv outermost portions 15 and 21 of the elastomeric members.

After the elastomeric means has redistributed its volume and taken up the previously mentioned small voids, any further drawing pressure provided by the clamp assembly 30 will exert further compressive forces on the elastomer. These further compressive forces cause the seated portions 24 and 28 of the elastomeric members to expand the support pockets 40 and 42 and thereby deflect the flexible sealing flanges 22 and 26 generally radially outwardly into engagement with the internal sealing surfaces 50 of the conduits.

v The previously mentioned undercut grooves 17 and 19 provide a means for controlling the pressure on the flexible sealing flanges 22 and 26 once they are radially flexed responsive to axial pressure on the elastomer. Any further axial pressure on the elastomer will not be immediately transmitted to the flanges because the elastomer may first escape around lip portions 18 and 14 and tend to close the grooves 17 and 19. The existence of this escape route is insured because the previously mentioned conduit dimension d is greater than the axial extent d of the axially outermost portions 5 and 7 of the lip portions. Therefore, the conduit sealing shoulder cannot abut the lip portions and close the escape route.

It will be appreciated that the composite seal 8 is particularly adapted for use in high pressure fluid flow lines such as discharge lines for fracturing work. The internal ring 12 provides the desirable characteristics of a substantially rigid sealing member, while the elastomeric sealing member 16 and 20 minimize the problem caused by the fact that rigid sealing members do not always conformingly engage with surfaces to be sealed.

The outward radial deflection of the flexible sealing flanges 22 and 26 does not affect the internal diameter 32 of the sealing ring. Therefore, the possibility of creating turbulence at the conduit joint is minimized.

Furthermore, since the deflection of sealing flanges 22 and 26 forms a second seal in addition to the first seal formed by the elastomeric means, the danger of losing the seal due to fatigue or overstressing of the metal flanges is eliminated.

In order to reduce the possibility of undesirable diametn'cal or directional changes at the conduit joint, seal ring 12 is provided with an alignment member 39. Member 39 extends generally axially outwardly from the central rim portion 34, and contacts the opposing end faces 6 of the conduit parts when they are drawn together by the clamp assembly 30. In this way, the conduit parts 2 and 10 are aligned with respect to the sealing member 8.

If an alignment member 39 is not included in the seal 8, then it is not necessary for the conduit dimension d, to be less than the seal dimension d In this case the overall axial dimension of the seal, when the elastomer is uncompressed, should be greater than the distance between the internal sealing shoulders 48 of the conduit parts 2 and 10 when they are joined, in order for compression to occur. Furthermore, in order to provide an escape route for the elastomer, the distance between the shoulders 48 when the conduit parts are joined should be greater than the overall axial extent of the lip portions of the seal.

OPERATION METHOD OF ASSEMBLY To assemble the seal unit of the present invention, composite seal 8 is first inserted into the sealing cavity 9 of the conduit part 2. Because of the dimensions of the seal 8, the elastomeric member 16 will contact the sealing shoulder 48 of the conduit sealing cavity before the rib means 39 of the seal contacts the end face 6 of the conduit. Next, conduit part 10 is slipped over the exposed end of the seal 8 until its internal sealing shoulder bottoms on the elastomeric member 20. The clamping assembly 30 is then placed into engagement with the projections 52 and 54 on the conduit parts. An initial drawing force provided by the clamping assembly 30 exerts compressive longitudinal forces on the elastomer, causing it to flow slightly and fill any small voids previously existing between the' internal sealing surfaces of the conduits and the elastomeric members 16 and 20. Any further force tending to draw the conduit parts 2 and 10 together causes the elastomer to further redistribute its volume because of the increased longitudinal compressive forces. Such a redistribution of volume causes the support pockets 40 and 42 to be expanded by the seated portions 24 and 28 of the elastomer, and to deflect flexible sealing flanges 22 and 26 radially outwardly into sealing engagement with the mating internal sealing surfaces 50 of the conduits. Rib means 39 acts as an alignment member for the conduit parts with respect to the composite seal 8.

SUMMARY OF ADVANTAGES It will be seen that in following the present invention, a seal assembly which is particularly effective in fluid flow line connections is provided.

Of particular significance is the provision of a leak proof seal with both the strength and rigidity of a relatively hard seal member and having the added advantage of minimizing the possibility of any voids occurring between an elastomeric seal and its mating conduit surfaces.

Also of importance in this connection is the provision of flexible sealing flanges as a second independent seaL-Since theseflanges deflect radially outwardly of the conduit flow path, there is little danger of a diameter change at the conduit joint or of the resulting turbulence caused by such a diameter change. 7

Other advantages are provided by the alignment rib means which aligns the conduit parts with respect to the seal member.

Furthermore, all sealing surfaces of the conduit parts are in a female cavity and will not be subjected to damage during handling;

A particular advantage in the method of assembling the seal unit of the present invention is the insurance of a fail-safe, leak-proof seal by drawing the conduit parts together to first cause theelastomer to conformingly engage the internal conduit sealing surfaces, and then drawing the conduit parts further together to cause the flexible sealing flanges to form a second seal.

Although the invention has been described with reference to one preferred embodiment and method, it will be appreciated by those skilled in the art that additions, modifications, substitutions, deletions and other changes not specifically described may be made which fall within the spirit of the invention as defined in the following claims.

We claim:

1. In a method for assembling a seal unit wherein the seal .unit includes two opposed conduit parts and a composite sealing ring adapted to be interposed between the conduit parts, and wherein the sealing ring includes an elastically deformable material on the outer periphery thereof and flexible sealing flanges on the outer periphery of the ring extending about at least a contacts the internal sealing surface of the one conduit part,

placing the second conduit part over the exposed portion of the seal to cause the internal sealing surface of the second conduit part to contact the elastically deformable material,

drawing the two conduit parts together to thereby cause the elastically deformable material to conformingly contact the internal surfaces of the conduit parts, and

drawing the two conduit parts further together to cause the elastically deformable material to flex the-sealing flanges of the composite sealing rings into engagement with the internal sealing surfaces of the conduit parts.

2. A method for assembling a seal unit according to claim 1 wherein the composite sealing ring includes rib means adapted to contact oppositely disposed end surfaces of the conduit parts, the method further including the step of:

utilizing the rib means to align the conduit parts with respect to the composite sealing ring while drawing the two conduit parts together by an amount sufficient to cause the end surfaces of the conduit parts to engage the rib means.

3. A method according to claim 2 wherein the internal diameter of the seal ring and the diameter of the flow passages in the conduit parts are substantially the same the in th includin the ste of:

utilizing e n means t main n the flow passages in axial alignment.

4. The method according to claim 1 wherein the sealing ring includes a central rib portion and two generally axially disposed lip portions, the method including the step of:

maintaining the lip portions substantially stationary with respect to the rib portion during flexing of the sealing flanges. 

1. In a method for assembling a seal unit wherein the seal unit includes two opposed conduit parts and a composite sealing ring adapted to be interposed between the conduit parts, and wherein the sealing ring includes an elastically deformable material on the outer periphery thereof and flexible sealing flanges on the outer periphery of the ring extending about at least a portion of the deformable material, the method comprising: partially inserting the seal into the cavity of one conduit part until the elastically deformable material contacts the internal sealing surface of the one conduit part, placing the second conduit part over the exposed portion of the seal to cause the internal sealing surface of the second conduit part to contact the elastically deformable material, drawing the two conduit parts together to thereby cause the elastically deformable material to conformingly contact the internal surfaces of the conduit parts, and drawing the two conduit parts further together to cause the elastically deformable material to flex the sealing flanges of the composite sealing rings into engagement with the internal sealing surfaces of the conduit parts.
 2. A method for assembling a seal unit according to claim 1 wherein the cOmposite sealing ring includes rib means adapted to contact oppositely disposed end surfaces of the conduit parts, the method further including the step of: utilizing the rib means to align the conduit parts with respect to the composite sealing ring while drawing the two conduit parts together by an amount sufficient to cause the end surfaces of the conduit parts to engage the rib means.
 3. A method according to claim 2 wherein the internal diameter of the seal ring and the diameter of the flow passages in the conduit parts are substantially the same, the method including the step of: utilizing the rib means to maintain the flow passages in axial alignment.
 4. The method according to claim 1 wherein the sealing ring includes a central rib portion and two generally axially disposed lip portions, the method including the step of: maintaining the lip portions substantially stationary with respect to the rib portion during flexing of the sealing flanges. 